1. Field of the Invention
The invention relates to apparatus for optically measuring displacement, obliguity and/or contour of a surface.
2. Brief Description of the Prior Art
Optical displacement or range finders using a triangulation technique are well known in the art. See e.g., U.S. Pat. Nos. 3,671,126 to Erb and 3,692,414 to Hosterman et al. Some of these devices have included the capability to gauge the surfaces tilt or contour. See e.g., U.S. Pat. Nos. 3,523,736 to Bottomley, 3,734,626 to Roberts et al., 3,885,875 to Rosenfeld et al., and 3,894,802 to Higgins. At least one patent, Higgins '414, supra, has disclosed a circular sweep in conjunction with triangulation to increase the scan range of the instrument, but not for the purpose of gauging tilt or contour. None have disclosed a projected ring of light for the purpose of simultaneous measurement of displacement and obliquity or contour.